Apparatus for heating fluids



April 3, 1945.

J. s. WALLIS El AL APPARATUS FOR HEATING FLUIDS Filed Jan. 18, 1945 2 She'ets-Sheet l IN VEIVTOfiS.

477' NE Y.

April 3, 5- J. S. WALLIS ETAL 2,372,991

APPARATUS FOR HEATING FLUIDS Filed Jan. 18, 1943 2 Sheets-Sheet 2 12 2 my QV/ ,a ww Jo/m .5. 14/4/05 John Thrackmorfon arm 5) Patented Apr. 3, 1945 APPARATUS FOR HEATING FLUIDS John s. Wallis, Darien, and John w. ramsmorton, Wilton, Conn., asslgnor to Petra-chem Process Company, Incorporated, a corporation of Delaware Application January 18, 1943, Serial No. 472,677

6 Claims.

Our invention relates to improvements in the heating of fluids, and refers more particularly to a heater construction which provides for the passage of two separate fluids through the heater in a plurality of separate streams, and the combination of the separate fluid streams in a mixing or accumulating stage after the heating period has elapsed.

The invention also provides for cooling or quenching the heated fluids after a predetermined period of heating.

At the present time there is a requirement for a heater capable of raising the temperature of fluids rapidly and uniformly to a relatively high point of the order of 1000 to 1500 F. with additional facilities for combining the heated materials and cooling or quenching the mixtures after predetermined time periods have elapsed.

Under certain conditions it has been found necessary to combine, mix or react fluids of different character to produce solutions, reactions or ultimate products of a desired character, and provide means for heating the separate fluid streams prior to their combination and cooling them after mixing.

Where temperatures are above 1000 F. the relationship between the heating surface, reaction time and the heat transfer rate all become important and critical factors. Such reactions generally require minimum time under temperature, which necessitates the use of small tubes, low pressure drop and high transfer rates through the heating zone. On occasions it is advantageous under some conditions to reduce the temperature as quickly as possible upon discharge from the heating zone, or as soon as the desired temperature has been reached.

In other types of reactions, it may be desirable to heat the fluids in separate coils to predetermined temperatures and combine them immediately at given temperatures and pass the mixture through additional heat absorbing surface, before arresting the reaction.

For example, in the conversion of light hydrocarbons we may heat naphtha to 1350 F. in one coil and normally gaseous hydrocarbons to 1500 F. in an adjacent coil in the same heater. two are combined at the furnace outlet, one type of reaction results while a very diflerent reaction follows if the materials are combined in the furnace at the predetermined temperatures and the 'mixture subjected to additional heat absorption before arresting the reaction. These different types of reactions are a governing factor in the composition of exit fluid and to a great extent If the ical construction requiring relatively low capital cost and low upkeep expense.

The heating elements used for heating the fluids are easily removed from the heater for cleaning or repair.

Other objects and advantages of the invention will be readily apparent from the following description.

In the accompanying drawings which form part of the instant specification and are to be read in conjunction therewith,. and in which like reference numerals are used to indicate like parts in the various views;

Fig. 1 shows a. side sectional elevation of the heater. I

Fig. 2 is a developed view of the heating elements shown in Fig. l.

Fig. 3 is a view taken along the line 3-3, Fig. 2.

Figs. 4 and 5 are modifications of Fig. 2 showing the joining Of separate .tube sections at different locations.

Fig. 6 is an elevational view similar to Fig. 1 in which the lower circular manifold has been replaced by an accumulator tank.

Fig. 7 is a view taken along the line 1-4, Fig. 6, in the direction of the arrows.

Fig. 8 is a view taken at the same location as Fig. 7 but showing a modified manner of joining the two sets of pipe sections prior to connection with the accumulator tank.

Referring to the drawings, the heater consists 'of a cylindrical casing ill, lined with insulation II and flrebrick J2. Around the interior of the casing and adjacent the wall of flrebrick are arranged a plurality of separate tube sections IS. The heat is supplied to the interior of the chamber by means of directional burners, shown at II, the number of burners depending upon the size of the heater and the service required.

In the top of the chamber is a conical baflle is which diverts the combustion gases as they pass upwardly through the chamber, rendering tubes. In order to increase the efllciency of the 'tubes the upper portion of the tubes adjacent the base of the conewhere they aresubjected principally to convection heat, the exposed surface of the tubes may be covered with fins or other type of extended surface.

On top of the heater is a breeching l6 surpipes 20 and 2|.

mounted by a stack H. In the upper part of the heater are two circular manifolds l8 and I9. To manifold l8 are connected inlet pipes 20, and to manifold l9 are connected inlet pipes 2|.

In the bottom of the heater shown in Fig. 1 is a single circular manifold 22, into which are connected discharge pipes 23 and inlet pipes 24.

In the modification shown in Fig. 4, the tube sections are joined prior to their being connected to the lower manifold.

In Fig. 5 there is shown a union of the tube sections in the heating zone and a heating section or tube carrying the mixed fluids located in the heater in which the mixture is heated prior to introduction into the lower manifold.

In both of these modifications the time period of heating and the location at which the fluids are mixed is governed by the particular method employed and whether the fluids must be combined before cooling or whether additional heating is required after mixture.

In Fig. 6 the lower circular manifold 22 is replaced by an accumulator tank 25 which in the drawings is conveniently shown as a vertical cylindrical tank located immediately below the heater. The separate tube sections l3 connected at their upper ends to the manifolds l8 and i9 discharge through connections I3a into the upper part of the accumulator. An outlet pipe 23.from the bottom of the accumulator permits withdrawal of the mixture, and an inlet pipe 24 furnishes an inlet for the introduction of a cooling or quenching liquid, such as that admitted through pipe 24 to the manifold, as shown in Figs. 1 to 5, inclusive. Although but a single inlet is shown in Fig. 6, it is contemplated that this pipe may be enlarged or the cooling fluid introduced through a plurality of pipes in order to effect immediate quenching of the fluids discharged into the accumulator from the heater.

In the modified form of construction shown in Fig. 8, tube sections l3 connected to the separate manifolds l8 and I9 are joined in a Y-pipe I3b manifold 22 or accumulator 25 and are withdrawn therefrom through pipes 24. As suggested, a cooling fluid may be introduced to the manifold 22 or accumulator 25 through pipes 24 to arrest and quench the fluids upon their arrival at these lower receptacles.

As indicated heretofore, processes essential to the petroleum and chemical industries often require that different fluids be heated to high tem-- peratures, and combined during heating or immediately thereafter. Under certain conditions it may be desirable also to cool or quench the mixed liquids when they hav arrived at a predetermined temperature. The heater shown provides a construction in which fluids of different types may be heated in the manner suggested and combined and cooled as desired. The period of time, the rate of heating and other factors may be governed by the length of the tubes, size of the tubes, and other details of construction according to the requirements of the process.

It will be understood that certain feature and subcombinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is, therefore, to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, we claim:

1. A heater construction comprising a cylindrical combustion chamber, a, heat source within said chamber, two separate sets of vertical tube banks located adjacent the inner combustion chamber wall and each having inlet and outlet ends, separate inlet manifolds and a single outlet accumulator, the inlet end of one set of tube and flow into the accumulator through a single connection. This construction is useful where a mixture is desired before the materials are cooled.

It is contemplated also that this union of the tube sections may be made within the heater, as shown in Fig. 5, in order that the mixture will undergo heating after the fluids have been combined and considerably prior to their being discharged into the accumulator where the reaction is arrested by cooling.

In operation, two different types of fluid are introduced to the manifolds l8 and I9 through One set of pipe sections [3 have their upper extremities connected to manifold [8, while the second set of the heating elements or pipe sections have their upper extremities con-- nected to manifold IS. Th separate fluids introduced to the two manifolds flow down through the pipe sections to which the manifolds are connected, being heated during their travel through the tube sections. Each tube section preferably has a plurality of vertical passes through the heating chamber, as shown in Fig. 2.

During passage of the fluids through the heater, they are brought into heat exchange relation with the combustion gases generated in burners H. The combustion or heating gases pass upwardly through the heater, being diverted outwardly by baffle I5. The flue gases pass of! from the top of the heater through breeching I6 and stack II.

The separate fluids passing through the tube sections are discharged either into the lower drical combustion chamber, a heat source within said chamber, two separate 'sets of vertical tube banks located adjacent the inner combustion .chamber wall and each having-inlet and outlet drical combustion chamber, a. heat source within said chamber, two separate sets of vertical tube banks located adjacent the inner combustion chamber wall and each having inlet and outlet ends, separate inlet manifolds and a single outlet accumulator, the inlet end of one set of tube banks connected to one inlet manifold, the inlet end of the second set of tube banks connected to the other inlet manifold, the outlet ends of both sets of tube banks connected to the outlet accumulator, means for introducing separate streams of fluids to the inlet manifold, means for withdrawing the mixed fluids from the accumulator, and means for. introducing a quench medium to the outlet ends of the tube banks ahead of their connection to the accumulator. 4. A heater construction comprising a cylindrical combustion chamber, a heat source within said chamber, two separate sets of vertical tube banks located adjacent the inner combustion chamber wall and each having inlet and outlet ends, separate inlet manifolds and a single outlet accumulator, the inlet ends of one set of tube banks connected to one inlet manifold, the inlet ends of the second set of tube banks connected to the other inlet manifold, the tubes of one bank of a set merged with the tubes of another bank of the other set to form a plurality of merger tubes located within the combustion chamber and having single outlet ends, said outlet ends connected to the outlet accumulator.

5. A heater construction comprising a cylindrical combustion chamber, a heat source within said chamber, two separate sets of vertical tube banks located adjacent the inner combustion chamber wall and each having inlet and outlet ends, separate inlet manifolds and a single outlet accumulator, the inlet ends of one set of tube banks connected to one inlet manifold, the inill let ends of the second set of tube banks connected to the other inlet manifold the tubes of one bank connected at an intermediate point with the tubes of the other bank to form a plurality of merger tubes located within the combustion chamber and having single outlet ends, said outlet ends connected to the outlet accumulator, and means for introducing a quench medium to the accumulator.

6. A heater construction comprising a cylindrical combustion chamber, a heat source within said chamber, two separate sets of vertical tube banks-located adjacent the inner combustion chamber wall and each having inlet and outlet ends, separate inlet manifolds and a single outlet accumulator, the inlet ends of one set of tube banks connected to one inlet manifold, the inlet ends of the second set of tube banks connected to the other inlet manifold the tubes of one bank connected at an intermediate point with the tubes of the other bank to form a plurality of merger tubes located within the combustion chamber and having-singleoutlet ends, said outlet ends connected to the outlet accumulator, and means for introducing a quench medium to the outlet ends of the merger tubes ahead of their connection to the accumulator.

JOHN S. WALLIS. JOHN W. 'IHROCKMORTON. 

